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authorChristoph Hellwig <hch@lst.de>2019-04-29 09:16:42 -0500
committerChristoph Hellwig <hch@lst.de>2019-06-25 07:54:06 +0200
commit4a54d16f615f41489b2ecbc940f6eb2618ddafd6 (patch)
treee12a8aa22cac1d57f7135ada2284801a5f1db8b9 /kernel/dma
parent591fcf3b301b3396d96f082298a9e8403c027d3f (diff)
downloadlinux-4a54d16f615f41489b2ecbc940f6eb2618ddafd6.tar.bz2
dma-mapping: truncate dma masks to what dma_addr_t can hold
The dma masks in struct device are always 64-bits wide. But for builds using a 32-bit dma_addr_t we need to ensure we don't store an unsupportable value. Before Linux 5.0 this was handled at least by the ARM dma mapping code by never allowing to set a larger dma_mask, but these days we allow the driver to just set the largest supported value and never fall back to a smaller one. Ensure this always works by truncating the value. Fixes: 9eb9e96e97b3 ("Documentation/DMA-API-HOWTO: update dma_mask sections") Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
-rw-r--r--kernel/dma/mapping.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index f7afdadb6770..1f628e7ac709 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -317,6 +317,12 @@ void arch_dma_set_mask(struct device *dev, u64 mask);
int dma_set_mask(struct device *dev, u64 mask)
{
+ /*
+ * Truncate the mask to the actually supported dma_addr_t width to
+ * avoid generating unsupportable addresses.
+ */
+ mask = (dma_addr_t)mask;
+
if (!dev->dma_mask || !dma_supported(dev, mask))
return -EIO;
@@ -330,6 +336,12 @@ EXPORT_SYMBOL(dma_set_mask);
#ifndef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
int dma_set_coherent_mask(struct device *dev, u64 mask)
{
+ /*
+ * Truncate the mask to the actually supported dma_addr_t width to
+ * avoid generating unsupportable addresses.
+ */
+ mask = (dma_addr_t)mask;
+
if (!dma_supported(dev, mask))
return -EIO;